key index

1. The index function is applied to index columns. In addition to the ordered search mentioned above, the database can greatly improve the query efficiency by using various fast locating technologies. In particular, when the data volume is very

This article mainly introduces the analysis and solution of MySQL deadlock to coders. For more information about coders, see the next article. MySQL deadlock is a problem that many programmers often encounter in project development. The following

1. ALTER TABLEAlter table is used to create a common index, a UNIQUE index, or a primary key index. Alter table table_name add index index_name (column_list)Alter table table_name add unique (column_list)Alter table table_name add primary key

Multi-version concurrency control technology is used by many database or storage engines, such as Oracle, ms SQL Server 2005 +, PostgreSQL, Firebird, InnoDB, Falcon, pbxt, Maria and so on. The new database storage engine uses multi-version instead

SQL Application and Development: (9) Improving efficiency indexes and SQL Indexes In a database, an index is a special object. It is a database structure that can accelerate data retrieval. It can quickly find the desired content from a large amount

1. IndexingIn addition to the ordered search mentioned above, the database can greatly improve the query efficiency by using various fast locating technologies. In particular, when the data volume is very large and the query involves multiple tables,

The application of B + tree in database {Why use B + trees? Concise, because: 1. The file is large and cannot be stored in memory, so it is stored on disk2. The structure of the index minimizes the number of disk I/O accesses during the lookup

1. Why Use indexes:The index in the database object is actually similar to the directory of the book, mainly to improve the speed of retrieving data from the table. Because the data is stored in a database table, the index is created on a database

In computer science, a lock is a synchronization mechanism used to forcibly restrict access to resources in the execution of multiple threads, which is used to guarantee the satisfaction of mutex requirements in concurrency control. In the DBMS,

Problem: A large number of recent errors are occurring Com.mysql.jdbc.exceptions.jdbc4.MySQLTransactionRollbackException:Deadlock found when trying to get lock; Try restarting transaction at Sun.reflect.NativeConstructorAccessorImpl.newInstance0

MyISAM and InnoDB are the two main engines of the MySQL database, MyISAM is the default engine prior to the MYSQL5.5 version, and InnoDB is the MySQL 5.5 version of the default engine.The differences between the two engines are as follows:

1. MyISAM: The default table type, which is based on the traditional ISAM type, ISAM is an abbreviation for indexed sequential access method (indexed sequential access methods), which is the standard way to store records and files. It is not

The difference and choice between MyISAM and InnoDB, detailed summary, performance comparisonJune 25, 2015 21:58:42 read: 1827 more personal Category: MySQL1. MyISAM: The default table type, which is based on the traditional ISAM type, ISAM is an

An index is a data structure used by the storage engine to quickly find records, which is the basic function of an index.Indexes are critical for good performance. Especially when the amount of data in a table is increasing, the impact of indexes on

(GO) view creation and deletion of MySQL index1． Index functionIn addition to the ordered lookups mentioned above, the database uses a variety of fast location techniques to greatly improve the query efficiency. In particular, when the amount of

Indexes are the primary means of accelerating queries, especially for queries involving multiple tables. In this section, you will describe the role of the index, its characteristics, and the syntax for creating and deleting indexes.13.4.1 using

1. Index function In addition to the ordered lookups mentioned above, the database uses a variety of fast location techniques to greatly improve the query efficiency. In particular, when the amount of data is very large and the query involves more

In the database, the index is a special object, it is a database structure that can speed up the data retrieval, it can quickly find the necessary content from the large amount of data, make the data query without retrieving the whole database. An

What is an index? Take the directory pages (indexes) of the Chinese dictionary for example: just as the Chinese characters in the Chinese Dictionary are stored by page, the data records in SQL Server are also stored by PAGE, and the size of each

 Indexes are the main means to accelerate queries, especially for queries involving multiple tables. This section describes the functions and features of indexes and the syntax for creating and deleting indexes. 13.4.1 optimize queries using